I designed a functional model of a plant growing system that, with modifications, would work in outer space. As a high school student, I made it as project to see how well my design would work. The biggest advantage of a future Space Garden is the amount of space it saves by combining the root spaces of two plant growth areas.

Supplies

Foam insulation
Satin pins
Empty mouthwash bottle
Reusable plastic straw
Cotton balls
Seeds
Hydroponic nutrients
Light source

Step 1: Building the Frame

The frame is built entirely from foam insulation and satin pins. I was unable to find any materials that were cheaper, but still allowed me to customize my frame. I had to keep in mind that I would need to easily access the growing plants when needed, but also have a spot to put a light source.

Step 2: Hole Drilling

I drilled ten holes on both of the big faces of the empty mouthwash bottle to insert seeds. The bottle will become the root space for future seedlings. I also drilled a hole on the top and bottom of the bottle for the purpose of attaching the root space to the frame. The final set of holes are in the frame itself.

Step 3: Add Cotton Balls

The plants will need something to take root onto to grow properly. On the International Space Station they use plant pillows to provide nutrients and water as well as something to grow on. I will use cotton balls because they are very absorbent and inexpensive. I stuffed as many cotton balls as possible in the root space to evenly distribute the available water and nutrients. I inserted small pieces of cotton balls into the holes of the root space to be sure that the seeds will have access to the water and nutrients.

Step 4: Preparing for Germination

To nourish the seedlings when they germinate, I dissolved the recommended amount of hydroponic nutrient in a gallon of water. Next I set the seeds on the cotton protruding from the holes on one side of the root space container. The last step to get the seeds to germinate is to add the nutrient solution to the root space.

Step 5: Final Construction

To hold the root space inside the frame, I hot glued pieces of reusable plastic straw in the top and bottom holes of the root space. I had to disassemble part of the frame to get the root space in it's place. The root space is able to rotate so that the seeds can face up or down. This is good, however the root space is heavier on one side so it tips to that side. To fix this I push a satin pin in the frame to keep the root space level.

Step 6: Lighting

When the seeds have germinated, the final thing they will need is a good light source. I use a basic grow light bulb in a heat lamp used for animals to provide light for the seedlings. The grow light provides the proper colors of light to satisfy plants' needs. Installation includes simply setting the light on the top of the frame and plugging it in. The light is shed on the seedlings through the opening in the frame.

Step 7: Plant Growing

Unfortunately, I had a low germination rate in the Space Garden. Only two of the cress plants made it to maturity, but at least it's a start. The most likely cause was that the seeds had a good soaking when they were planted but didn't have sustained water directly to their roots. To fix this I could have sown the seeds deeper into the cotton. Another improvement I would make to the design is a watering port to add more nutrient solution to the root space.

Step 8: Functions of the Future

The Space Garden is only a model for a possible growing system in space. It is not currently capable of growing plants in space, but as shown, It does work with the conditions provided by earth (gravity, air, and temperature). By modifying the system to allow plants to survive the conditions of space (controlling temperature, and air), the Space Garden can produce twice as many plants because it has a second side capable of growing plants. This two sided design allows for more space to be conserved by sharing root space. Since the root space can be rotated, one side can easily be designated for younger plants and the other for older plants until they are ready for harvest.